1. Field of the Invention
The present invention relates to a disk cartridge which accommodates, in the interior thereof, and protects a disk medium for recording of information.
2. Description of the Related Art
Conventionally, in 3.5-inch flexible disks (FDs), mini-disks (MDs) and the like, a disc-shaped disk medium is accommodated within a case. At the time of reading or recording information from or onto the disk medium, a recording member or a reading member of a drive device accesses the disk medium from an opening portion of the case. Further, a shutter member which opens and closes the opening portion is provided at the case. In the usual state, the shutter member is at a closed position and closes the opening portion. As needed, the shutter member is moved by (a shutter opening/closing mechanism of) the drive device to reach an open position, and the opening portion is opened.
At the case accommodating the disk medium, the two case members are combined such that an accommodating portion for a disk medium is formed therebetween. Because the two case members have respectively different configurations, the number of parts increases and the parts costs increase.
In order to prevent the opening portion from being opened needlessly, it is preferable to provide, at the case, a lock member for locking the shutter member, an urging member for urging the shutter member to the closed position, and the like. However, by providing such members, the number of parts increases, which leads to an increase in the costs for parts.
Moreover, because the number of work processes for assembling parts increases due to the increase in the number of parts, the assembly costs also increase. In addition, in recent years, it has become desirable to make disk media smaller sized. When, in accordance with this trend, the respective parts are also to be made small-sized, the assembly work becomes even more difficult.
The configuration of the cartridge case of the disk cartridge along the planar direction (the planar configuration) is substantially rectangular. On the other hand, the width of the opening of a disk cartridge loading portion of a disk drive device is slightly wider than the dimensions of the short sides of the cartridge case, and is narrower than the long sides of the cartridge case. In this way, when loading the disk cartridge into the drive device, it is possible to prevent the cartridge case from being inserted into the loading portion of the drive device in a state of being rotated 90° with respect to the correct direction of insertion, i.e., in the direction in which a long side of the cartridge case is inserted first.
However, when a user inserts the cartridge case into the loading portion of the drive device in a state of having rotated the cartridge case by 180° with respect to the correct direction of insertion, it is possible, from a dimensional standpoint, to insert the cartridge case into the loading portion of the drive device. Accordingly, in order to prevent such incorrect insertion of the disk cartridge, a detecting means must be provided at the drive device in order to detect a cartridge case which has been incorrectly inserted into the loading portion in a state of having been rotated by 180° with respect to the correct insertion direction. Such a means for detecting incorrect insertion may be, for example, a means which detects the insertion direction of the cartridge case by using an optical sensor or a magnetic sensor or the like. However, if such a means for detecting incorrect insertion is provided at the drive device, the structure of the drive device becomes complex, the number of parts increases and the cost of the device increases.
There are shutter opening/closing mechanisms of the above-described drive devices which, for example, open or close a shutter member by making a shutter opening/closing lever, which is formed in a pin-shape or a plate-shape, engage with the shutter member, and by moving the shutter opening/closing lever along the opening/closing direction of the shutter member.
In recent years, the development of small-sized disk cartridges and drive devices therefor has advanced as such small-sized disk cartridges and drive devices are utilized in mobile devices such as cellular phones and the like. As disk cartridges and drive devices have become more compact, of course, the shutter member at the disk cartridge and the shutter opening/closing lever at the drive device have also been made smaller. Such shutter members and shutter opening/closing levers have less relative dimensional accuracy and strength than shutter members and shutter opening/closing levers used in larger disk cartridges and drive devices. With such smaller structures, at the time of loading the disk cartridge into the drive device, it is difficult for the shutter opening/closing member to reliably be made to engage the shutter member.
Moreover, in a small-sized disk cartridge in which information can be recorded on and read out (played back from) both the obverse and reverse surfaces of the recording disk, usually, a window portion is formed in each of the obverse and reverse surfaces of the cartridge case, and a shutter member, for opening and closing the window portion, is disposed at each of the obverse side and the reverse side of the cartridge case. Accordingly, the configurations and dimensions of the shutter opening/closing lever and the shutter members are limited in order to, at the time of opening one shutter member by the shutter opening/closing lever, prevent the shutter opening/closing lever and the one shutter member from interfering with the other shutter member. When such limitations exist, it is extremely difficult to make the shutter opening/closing lever reliably engage with the shutter member when the disk cartridge is loaded into the drive device.
When a case, in which a disk medium is accommodated, is inserted into a drive device, the case is positioned within the drive device. Generally, a pair of reference holes for positioning are formed in the case along a direction orthogonal to the direction of insertion into the drive device, and positioning pins of the drive device can be fit into the reference holes.
Here, one reference hole is a completely circular portion, and the other reference hole is a flat oval portion. In this way, reference positioning of the case and the drive device is first carried out by the completely circular portion, and the flat oval portion absorbs the positional offset between the case and the drive device and the positional offset between the completely circular portion and the positioning pin when the case is tilted at the time of being loaded or discharged. In this way, galling between the positioning pin and the completely circular portion is mitigated.
When recording and playback are possible at both surfaces of the disk medium, there are cases in which the case is turned upside-down and inserted into the drive device. At such a time, the positions of the completely circular portion and the flat oval portion are reversed with respect to the positioning pins.
Thus, as shown in FIG. 18A, completely circular portions 500 and flat oval portions 502 are disposed so as to oppose one another. The completely circular portion 500 is disposed at a reference positioning pin 510 provided at a drive device (not shown), regardless of whether a case 504 (formed by a shell 506 and a shell 508) is upside-down or not.
However, as the case 504 is made to be ultra-compact, the case 504 is also made to be thinner. As shown in FIG. 18B, there are cases in which the distal end portions of the reference positioning pin 510 and a positioning pin 512 project from the shell 508 which is disposed at the lower side and reach the shell 506 disposed at the upper side.
In this case, the positional offset and the like between the completely circular portion 500 and the reference positioning pin 510 is absorbed at the positioning pin 512. Thus, regardless of the fact that the positioning pin 512 corresponds to the flat oval portion 502, the distal end portion of the positioning pin 512 fits together with the completely circular portion 500 of the shell 506, and there is the concern that problems will arise in the operations of loading and discharging the case 504.
Further, the case accommodating the disk medium is formed by fixing two shells (two case members) together by ultrasonic welding or the like.
A lock member which locks a shutter member in order to prevent inadvertent opening of the disk opening portion, an urging member which urges the shutter member toward its closed position, and the like are accommodated in the case. When the shells have been fixed together by ultrasonic welding, if the disk cartridge is deemed defective in a quality inspection, the parts thereof which could be used cannot be reused.
Thus, it is preferable to carry out ultrasonic welding after the disk cartridge has undergone a quality inspection. However, up until the time that the ultrasonic welding is carried out, the shells must be maintained in a temporarily fastened state so as to not come apart from one another.